According to https://secure.phabricator.com/book/phabricator/article/notifications/#installing-node-and-modu, NodeJS module ws is needed to be installed in directory
```
support/aphlict/server/
```
when it would be really great to be able to use the system-wide one to help getting assistance of package manager to get the lastest/safest and/or usable by every instance you have.